Tap water contains a certain amount of solubilized ions which upon water evaporation eventually deposit as salts such as calcium carbonate on hard-surfaces which are often in contact with water, resulting in an anaesthetic aspect of the surfaces. This limescale formation and deposition phenomenon is even more acute in places where water is particularly hard.
It is well-known in the art that limescale deposits can be chemically removed with acidic solutions, and a great variety of acidic limescale removal compositions have been described for this purpose.
It is also desirable that such liquid acidic compositions should have, in addition to the ability to effectively remove limescale deposits present on a surface, the ability to provide good shine to the surfaces treated. However, surface shine is often compromised because, when water comes in contact with hard-surfaces it has the tendency to form droplets on the surface rather than forming a thin film uniformly spread over the surface or to run off the surface. This results, as water evaporates, in precipitation of poorly water soluble inorganic salts such as calcium/magnesium carbonate and/or phosphate salts with consequent formation of watermarks on the surface and, eventually limescale deposits, resulting in an anaesthetic aspect of the surface.
It is thus an object of the present invention to reduce the formation of watermarks and/or limescale deposits on a hard-surface that has been treated with a liquid acidic composition and hence to provide improved shine to this surface. More particularly, it is an object of the present invention to provide liquid acidic compositions delivering improved shine to the surface treated while exhibiting excellent limescale removing performance. It is yet another object of the present invention to provide such liquid acid compositions in a convenient way so as to facilitate any hard-surface descaling operation therewith by the consumer.
The present invention overcomes these problems by formulating liquid acidic compositions comprising an acid, a polysaccharide polymer (0.001%-20%) and a vinylpyrrolidone homopolymer or copolymer (0.001%-20%), said compositions being packaged in a spray type-dispenser. Indeed, it has been found that the addition of a polysaccharide polymer, preferably xanthan gum, together with a vinylpyrrolidone homopolymer or copolymer, in a liquid acidic composition, reduces or even prevents the formation of limescale deposits on a surface having first been treated with such a composition. Also less formation of watermarks are observed on a surface having been first treated with the compositions as described herein and then contacted with water, for example, during a rinse operation, thereby providing improved shine to said surface.
Another advantage of the present invention is that the shine benefit delivered to a hard-surface treated with the compositions of the present invention persists even after several cycles of rinsing, thus providing long lasting protection against formation of watermarks and/or even limescale deposits on the surface, and hence long lasting shiny surfaces. In other words, the house wife will have the advantage to delay the next descaling operation. Advantageously, the shine benefits herein are obtained at very low total levels of both a polysaccharide polymer and a vinylpyrrolidone homopolymer or copolymer, in the acidic compositions of the present invention.
Another advantage of the liquid acidic compositions of the present invention is that the surfaces treated become smoother (this can be perceived by touching said surfaces). This may also contribute to convey to consumer perception of surface perfectly descaled.
Also it has surprisingly been found that the compositions according to the present invention deliver the benefits mentioned herein (e.g., reduction or prevention of the formation of watermarks and/or even limescale deposits, resulting in good shine benefit and even long lasting shine benefit), when used to treat a variety of surfaces including metal surfaces such as aluminium, chromed steel, stainless steel, synthetic materials like vinyl, linoleum, glazed or non-glazed ceramic tiles, and/or enamel surfaces.
In a preferred embodiment of the present invention, the compositions herein comprise maleic acid together with a second acid typically sulfamic acid. These compositions have been found to be particularly safe to various types of hard-surfaces treated therewith as well as milder to the skin.
Another benefit of the present invention is that the compositions herein are easily applied to the surface to treat while using a minimum amount of said composition, as compared to applying a liquid composition by directly pouring it onto the surface to treat, instead of spraying it according to the present invention. Also spraying the composition on the surface to treat allows to treat a larger area with a give amount of product versus pouring the liquid composition on the surface to treat. Furthermore, the risk of spillage as well as the tendency of the liquid compositions to be messy when applied onto the surface is reduced when said application is made by using a spray-type dispenser.
Advantageously, the liquid acidic compositions of the present invention are applied to the surfaces to treat by the means of a spray-type dispenser while being safe both to the user and to the surfaces treated therewith. Indeed, the acidic compositions herein may be sprayed onto the surfaces to treat with minimal inhalation by the user of said acidic compositions and thus by avoiding any potential health issue due to the presence of an acid in said compositions.